Information processing system, information management apparatus, and data transfer control method

ABSTRACT

An information processing system includes: a management apparatus coupled to nodes to execute data transfer, wherein the management apparatus preforms operations to: acquire data transfer information in which a priority level of data transfer and an identifier of a node that executes the data transfer are associated with an identifier of the data transfer; identify, when receiving an execution instruction of first data transfer, one or more first nodes that execute second data transfer having a lower priority level than a priority level included in information of the first data transfer based on the data transfer information; and transmit, to each of the one or more first nodes, a stop request to stop the second data transfer, and a transfer request including the information of the first data transfer and information of a portion to be executed by the first node of the first data transfer by the first node.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority of theprior Japanese Patent Application No. 2014-192397, filed on Sep. 22,2014, the entire contents of which are incorporated herein by reference.

FIELD

The embodiment discussed herein is related to an information processingsystem, an information management apparatus, and a data transfer controlmethod.

BACKGROUND

When data is transferred, the order of transfer is changed in accordancewith priority levels of transfer.

Related art is disclosed in Japanese Laid-open Patent Publication No.10-98605 or Japanese Laid-open Patent Publication No. 8-204732.

SUMMARY

According to an aspect of the embodiments, an information processingsystem includes: a management apparatus, coupled to a plurality of nodesconfigured to execute data transfer, configured to manage the pluralityof nodes, wherein the management apparatus preforms operations to:acquire data transfer information in which a priority level of datatransfer and an identifier of a node that executes the data transfer areassociated with an identifier of the data transfer; identify, whenreceiving an execution instruction of first data transfer, one or morefirst nodes that execute second data transfer having a lower prioritylevel than a priority level included in information of the first datatransfer based on the data transfer information; and transmit, to eachof the one or more first nodes, a stop request to stop the second datatransfer, and a transfer request including the information of the firstdata transfer and information of a portion to be executed by the firstnode of the first data transfer to be executed by the first node.

The object and advantages of the invention will be realized and attainedby means of the elements and combinations particularly pointed out inthe claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and arenot restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates an example of a system;

FIG. 2 illustrates an example of file copying;

FIG. 3 illustrates an example of a functional block of a front-endserver;

FIG. 4 illustrates an example of a functional block of an IO node;

FIG. 5 illustrates an example of a data structure;

FIG. 6 illustrates an example of a structure;

FIG. 7 illustrates an example of a data structure;

FIG. 8 illustrates an example of a structure;

FIG. 9 illustrates an example of a structure;

FIG. 10 illustrates an example of a process executed by a front-endserver;

FIG. 11 illustrates an example of a process executed by a front-endserver;

FIG. 12 illustrates an example of a process executed by a front-endserver;

FIG. 13 illustrates an example of a process executed by an IO node;

FIG. 14 illustrates an example of a process executed by an IO node; and

FIG. 15 illustrates an example of a functional block of a computer.

DESCRIPTION OF EMBODIMENT

For example, data transfer being executed is interrupted, and datatransfer having a higher priority level than a priority level of thedata transfer being executed is preferentially executed.

For example, a single apparatus may execute the above-mentioned datatransfer.

For example, in a distributed file system, file transfer is executed bya plurality of nodes included in the distributed file system in adistributed manner. For example, in the case where the plurality ofnodes transfer one file, each of the plurality of nodes transfers a partof the file, and the one file is thereby transferred as a whole.

FIG. 1 illustrates an example of a system. In FIG. 1, a distributed filesystem is illustrated. A front-end server 1 is coupled to, for example,input/output (IO) nodes 31 to 34 that execute file copying, a first filemanagement apparatus 5 that includes a first file storage unit 51, and asecond file management apparatus 7 that includes a second file storageunit 71 via a network 6, such as a local area network (LAN). Thefront-end server 1 is coupled to, for example, a network 8, which is theInternet, and a user terminal 9 is coupled to the network 8. In FIG. 1,although the number of IO nodes is four, the number may be any number.

The user terminal 9 transmits an execution instruction containinginformation of file copying to be executed to the front-end server 1.When the front-end server 1 receives the execution instruction from theuser terminal 9, the front-end server 1 assigns IO nodes to the filecopying specified in the execution instruction. The IO nodes 31 to 34execute the file copying in accordance with assignments made by thefront-end server 1.

FIG. 2 illustrates an example of file copying. In FIG. 2, file copyingexecuted by the IO nodes 31 to 34 is illustrated. The IO nodes 31 to 34copy a copy source file stored in the first file storage unit 51 to thesecond file storage unit 71. The size of data copied by each IO node maybe substantially the same as the size of data copied by another IO node.A copy destination file is divided into 24 blocks, and each IO nodecopies data of one block in one copying operation. Shaded portions inthe copy destination file denote portions in which copying has beencompleted. When one copying operation is completed, each IO node checkswhether or not it has received a stop request to stop file copying fromthe front-end server 1.

FIG. 3 illustrates an example of a functional block of a front-endserver. The front-end server 1 includes a reception unit 101, amanagement unit 102, a server data storage unit 103, a transmission unit104, a first queue 105, and a second queue 106.

The reception unit 101 receives an execution instruction of file copyingfrom the user terminal 9, and outputs it to the management unit 102.

The management unit 102 executes processing based on the executioninstruction received from the reception unit 101, and, in accordancewith a processing result, stores a copying request in the first queue105 or outputs a copying request to the transmission unit 104. Themanagement unit 102 generates copying requests based on informationcontained in progress data received from the IO nodes 31 to 34, andstores the generated copying requests in the second queue 106.

The transmission unit 104 transmits the copying request received fromthe management unit 102 to an IO node that deals with the copyingrequest. The transmission unit 104 transmits the copying request storedin the first queue 105 and the copying requests stored in the secondqueue 106 to IO nodes that deals with the respective copying requests.

FIG. 4 illustrates an example of a functional block of an IO node. TheIO node 31 includes a copying unit 311 and a node data storage unit 312.The copying unit 311 executes file copying based on data received fromthe front-end server 1, and stores performance information representinga performance result of the file copying in the node data storage unit312. Functional blocks of the IO nodes 32 to 34 may be substantially thesame as or similar to the functional blocks of the IO node 31.

FIG. 5 illustrates an example of a data structure. In FIG. 5, thestructure of data stored in the server data storage unit 103 illustratedin FIG. 3 is illustrated. Data is stored in the server data storage unit103 as a structure. The structure may be generated for each executioninstruction, and contains a copy source file name, a copy destinationfile name, data indicating IO node information, such as a pointer, apriority level, and a file size. The IO node information contains anidentifier of an IO node, such as an IP address, data indicating requestinformation, such as a pointer, data indicating performance resultinformation, such as a pointer, and data indicating a next IO node, suchas a pointer. The request information contains a start offset, such as aposition at which copying is started, and the size of data to be copied.The performance result information contains a start offset and the sizeof copied data. FIG. 6 illustrates an example of a structure. In FIG. 6,a structure stored in the server data storage unit 103 is illustrated. Acode 6001 illustrated in FIG. 6 may be an example of an element 5001illustrated in FIG. 5. A code 6002 illustrated in FIG. 6 may be anexample of an element 5002 illustrated in FIG. 5. A code 6003illustrated in FIG. 6 may be an example of an element 5003 illustratedin FIG. 5. A code 6004 illustrated in FIG. 6 may be an example of anelement 5004 illustrated in FIG. 5.

FIG. 7 illustrates an example of a data structure. In FIG. 7, thestructure of data stored in the node data storage unit 312 illustratedin FIG. 4 is illustrated. Data is stored in the node data storage unit312 as a structure. The structure may be generated for each copyingrequest received from the front-end server 1, and contains a copy sourcefile name, a copy destination file name, information representing a filedirectory of a copy destination file, a priority level, the size of datato be written at one time, data indicating request information, such asa pointer, and data indicating performance result information, such as apointer. The request information contains a start offset and the size ofdata to be copied. The performance result information contains a startoffset and the size of copied data. FIG. 8 illustrates an example of astructure. In FIG. 8, an example of a portion corresponding to anelement 7001 illustrated in FIG. 7 in a structure stored in the nodedata storage unit 312 is illustrated. An element 7002 illustrated inFIG. 7 may be similar to the element 5003 illustrated in FIG. 5. Anelement 7003 illustrated in FIG. 7 may be similar to the element 5004illustrated in FIG. 5. As “char srcpath” and “char dstpath”, valuesusable by each IO node in the distributed file system may be set.

FIG. 9 illustrates an example of a structure. In FIG. 9, a structureabout data exchanged between the front-end server 1 and the IO nodes 31to 34 is illustrated. The data exchanged between the front-end server 1and the IO nodes 31 to 34 is generated as a structure. In the structure,“int64_t_ndata” denotes a setting value about copying of data, and“int64_t priority” denotes a priority level.

FIGS. 10 to 12 each illustrate an example of a process executed by afront-end server. In the distributed file system, file copying having afirst priority level and file copying having a second priority level,which is a lower priority level than the first priority level, may beexecuted.

When the user terminal 9 transmits an execution instruction, thefront-end server 1 executes a process. The reception unit 101 of thefront-end server 1 receives an execution instruction of file copyingfrom the user terminal 9 (FIG. 10: operation S1), and outputs it to themanagement unit 102. The execution instruction of file copying maycontain, for example, a copy source file name, a copy destination filename, a priority level, and a file size.

The management unit 102 identifies a priority level contained in theexecution instruction received from the reception unit 101 (operationS3). The management unit 102 determines, by using data stored in theserver data storage unit 103, whether or not file copying having a lowerpriority level than the priority level identified in operation S3 isbeing executed (operation S5). For example, as for file copying beingexecuted, structures are stored in the server data storage unit 103, andthus, the management unit 102 compares a priority level in eachstructure with the priority level identified in operation S3.

In the case where file copying having a lower priority level than thepriority level identified in operation S3 is not being executed(operation S5: No route), the case is a state in which the prioritylevel identified in operation S3 is the second priority level, or astate in which the priority level identified in operation S3 is thefirst priority level and file copying having the second priority levelis not being executed. Hence, the management unit 102 generates acopying request based on information contained in the executioninstruction, for example, a copy source file name, a copy destinationfile name, a priority level, and a file size, and stores it in the firstqueue 105 (operation S7). The process proceeds to a process illustratedin FIG. 11 via a terminal A. The process ends.

In the case where a certain state is entered, for example, in the casewhere an IO node which is not executing file copying occurs, or in thecase where a certain time arrives, the copying request stored in thefirst queue 105 is extracted by the transmission unit 104, andtransmitted to the IO node. In the case where there are a plurality ofIO nodes which are not executing file copying, the transmission unit 104may transmit a copying request to each of the plurality of IO nodes. Inthis case, the transmission unit 104 adds information of the size ofdata to be copied by each IO node and a start offset to the copyingrequest to be transmitted to each IO node.

In the case where file copying having a lower priority level than thepriority level identified in operation S3 is being executed (operationS5: Yes route), the priority level identified in operation S3 is thefirst priority level. The management unit 102 identifies, from theserver data storage unit 103, IO nodes that execute file copying havinga lower priority level than the first priority level, for example, thesecond priority level (operation S9).

The management unit 102 calculates, based on the information containedin the execution instruction, the number N (N is a natural number) of IOnodes that are to execute file copying having the first priority level(operation S11). For example, in the case where information of a timewhen file copying is completed is contained in the executioninstruction, a transfer rate may be obtained by dividing the file sizeby a time period from the point of processing in operation S11 to thetime when file copying is completed. The number N of IO nodes that areto execute the file copying having the first priority level may becalculated by dividing the obtained transfer rate by a transfer rate ofone IO node. In the case where information of the number of IO nodesthat are to execute the file copying having the first priority level iscontained in the execution instruction, the information may be used. Inthe case where the information of the time when file copying iscompleted is not contained in the execution instruction, N=1 may be set.

The management unit 102 identifies one unprocessed IO node from amongthe IO nodes identified in operation S9, and adds it to an executionnode list (operation S13). The execution node list may be, for example,IO node information stored in the server data storage unit 103.

In the case where operation S13 is executed with respect to theexecution instruction received in operation S1 for the first time, themanagement unit 102 generates a structure for the execution instructionreceived in operation S1, and generates IO node information. In the casewhere this is not the first time to execute operation S13, IO nodeinformation is added to the already generated structure.

In operation S13, an IO node having the highest effective transfer rateamong unprocessed IO nodes may be identified based on positionalrelationships among a copy source file, a copy destination file, and theIO nodes. For example, information of effective transfer rates may beacquired by using measurements made in advance or the like.

The management unit 102 transmits a stop request to stop file copyingbeing executed to the IO node identified in operation S13. Themanagement unit 102 receives progress data representing the progress ofthe stopped file copying as a response to the stop request (operationS15).

The management unit 102 generates a copying request based on informationcontained in the progress data received in operation S15, and stores itin the second queue 106 (operation S17). The process proceeds tooperation S19 in FIG. 11 via a terminal B illustrated in FIG. 10. Theprogress data may contain, for example, a copy source file name, a copydestination file name, a priority level, a position at which copying hasbeen stopped, a remaining data size, and so forth.

In FIG. 11, the management unit 102 generates a copying requestcontaining the copy source file name, the copy destination file name,the priority level, a start offset, and a data size for the file copyinghaving the first priority level based on the information contained inthe execution instruction (FIG. 11: operation S19). The data size isobtained by dividing the file size by the number N of IO nodes that areto execute file copying. The start offset is obtained from the obtaineddata size and the number of IO nodes added to the execution node list.

The management unit 102 outputs the copying request generated inoperation S19 to the transmission unit 104. In response to this, thetransmission unit 104 transmits the copying request generated inoperation S19 to the IO node identified in operation S13 (operationS21).

The management unit 102 determines whether or not the number ofexecution nodes has reached N (operation S23). When the number ofexecution nodes has reached N (operation S23: Yes route), the processends because assignment of IO nodes to the file copying having the firstpriority level has been completed.

When the number of execution nodes has not reached N (operation S23: Noroute), the management unit 102 determines whether or not there is anunprocessed IO node (operation S25). When there is an unprocessed IOnode (operation S25: Yes route), the process returns to the process ofoperation S13 via a terminal C illustrated in FIG. 11 to deal with anext IO node.

When there is no unprocessed IO node (operation S25: No route), thenumber of IO nodes that are to execute the file copying having the firstpriority level may be insufficient. Because of this, the management unit102 identifies a start offset and a data size of a remaining portion ofthe file copying having the first priority level based on the datastored in the server data storage unit 103 (operation S27). For example,when a value obtained by multiplying the number of IO nodes assigned tothe file copying having the first priority level by the size of data tobe copied by one IO node is subtracted from the size of the file to betransferred by the file copying having the first priority level, thedata size of the remaining portion is obtained. The start offset isobtained from the size of the file to be transferred by the file copyinghaving the first priority level and the data size of the remainingportion.

The management unit 102 generates a copying request containing the copysource file name, the copy destination file name, the priority level,the start offset and the data size of the remaining portion, and soforth, and stores it in the first queue 105 (operation S29). Then, theprocess ends.

Through execution of the above processes, the file copying having thefirst priority level may be preferentially executed. File copying havingthe second priority level whose execution has been interrupted isresumed in another IO node, and thus completion of the file copyinghaving the first priority level may not be waited.

In FIG. 12, the front-end server 1 transmits the copying request storedin the second queue 106 to an IO node.

The management unit 102 detects the occurrence of an event (FIG. 12:operation S31). The event may be, for example, an event in which thefile copying having the first priority level is started, and is detectedby using a notification from an IO node that has started the filecopying having the first priority level. The notification from the IOnode contains, for example, the copy source file name, the copydestination file name, the priority level, and so forth.

The management unit 102 notifies the transmission unit 104 of the startof the file copying having the first priority level. In response tothis, the transmission unit 104 extracts a copying request for filecopying interrupted by the IO node that has started the file copyinghaving the first priority level from the second queue 106 (operationS33). The number of copying requests extracted from the second queue 106may be two or more.

The transmission unit 104 calculates a start offset from information ofa position at which copying has been stopped contained in the extractedcopying request, and adds information of the calculated start offset tothe copying request (operation S35). The start offset may be a positionone byte ahead of the position at which copying has been stopped.

The transmission unit 104 identifies an IO node that deals with thecopying request extracted in operation S33 (operation S37). In operationS37, a node other than the IO node identified in operation S13 isidentified. An IO node may be identified from among nodes other than theIO node identified in operation S13 based on loads on a network andprocessing loads of IO nodes that are estimated from positionalrelationships among a copy source file, a copy destination file, and theIO nodes. In this case, information on the loads on a network and theprocessing loads of IO nodes may be acquired by using measurements madein advance or the like. In operation S37, the same number of IO nodes asthe number of extracted copying requests may be identified.

The transmission unit 104 updates the data stored in the server datastorage unit 103 based on a processing result in operation S37. Thetransmission unit 104 transmits the copying request to the IO nodeidentified in operation S37 (operation S39). In operation S39, onecopying request is transmitted to one IO node. The process ends.

In the above process, interrupted file copying is resumed by an IO nodedifferent from an IO node that has executed the file copying, and thusthe file copying may not have to be started again from the beginning.

FIGS. 13 and 14 each illustrate an example of a process executed by anIO node.

An IO node, for example, the copying unit 311 of the IO node 31 receivesa copying request from the front-end server 1 (FIG. 13: operation S41).In response to this, the copying unit 311 transmits a response to thecopying request to the front-end server 1 (operation S43).

The copying unit 311 determines the size of data to be copied at onetime based on a priority level contained in the copying request(operation S45). For example, as the priority level decreases, the sizeof data to be copied at one time may be reduced. Such processing mayreduce a delay of a timing when file copying having the second prioritylevel is stopped in the case where a copying request for file copyinghaving the first priority level is made during the file copying havingthe second priority level.

The copying unit 311 executes one copying operation based on informationcontained in the copying request received in operation S41 (operationS47). The copying unit 311 stores performance result information of thecopying in the node data storage unit 312.

The copying unit 311 determines whether or not it has received a stoprequest from the front-end server 1 (operation S49). When a stop requesthas been received (operation S49: Yes route), the copying unit 311executes stop processing (operation S53). The process ends.

The copying unit 311 stops file copying being executed (FIG. 14:operation S61).

The copying unit 311 generates, for the file copying whose execution hasbeen stopped, progress data containing a copy source file name, a copydestination file name, a priority level, a position at which the copyinghas been stopped, and a remaining data size (operation S63). The copyingunit 311 transmits the progress data generated in operation S63 to thefront-end server 1 (operation S65). The process returns to the callingprocess.

In the above process, execution of the stopped file copying may be takenover by another IO node.

As illustrated in FIG. 13, in operation S49, when it is determined thatno stop request has been received (operation S49: No route), the copyingunit 311 determines whether or not file copying specified in the copyingrequest has been completed (operation S51). When the file copyingspecified in the copying request has not been completed (operation S51:No route), the process returns to the process of operation S47.

When the file copying specified in the copying request has beencompleted (operation S51: Yes route), the copying unit 311 readsperformance result information of the completed file copying from thenode data storage unit 312, and transmits a notification containing theread performance result information to the front-end server 1 (operationS55). The process ends. The management unit 102 of the front-end server1 updates the data stored in the server data storage unit 103 based onthe performance result information contained in the receivednotification.

In the above process, file copying having a relatively low prioritylevel may be interrupted, and file copying having a relatively highpriority level may be executed.

For example, the functional block configurations of the front-end server1, the IO node 31, the first file management apparatus 5, and the secondfile management apparatus 7 may not coincide with program moduleconfigurations.

The above-mentioned data retention configurations may be an example. Aslong as a processing result is not changed, the order of processes maybe changed, and processes may be executed in parallel.

The above-mentioned processes may also be applied to file transfer otherthan file copying, for example, file migration.

The front-end server 1 may receive an execution instruction from theuser terminal 9, and may also receive an input of an executioninstruction from a user who operates the front-end server 1.

The front-end server 1 may calculate a start offset in a copying requeststored in the second queue 106, and an IO node that has stopped filecopying may also calculate a start offset based on information of aposition at which the file copying has been stopped.

An IO node which is not executing processing when an executioninstruction for file copying having the first priority level is receivedmay execute the file copying having the first priority level.

In operation S29, the copying request may be stored as a first entry inthe first queue 105. Thus, copying for the remaining portion may also bestarted as soon as possible.

FIG. 15 illustrates an example of a functional block of a computer. Thefront-end server 1, the IO nodes 31 to 34, the first file managementapparatus 5, the second file management apparatus 7, and the userterminal 9 may be a computer apparatus. For example, as illustrated inFIG. 15, a memory 2501, a central processing unit (CPU) 2503, a harddisk drive (HDD) 2505, a display control unit 2507 connected to adisplay device 2509, a drive device 2513 for a removable disk 2511, aninput device 2515, and a communication control unit 2517 used forconnection to a network are coupled to one another with a bus 2519. Anoperating system (OS) and an application program for implementing theabove-mentioned processes are stored in the HDD 2505, and read from theHDD 2505 into the memory 2501 when executed by the CPU 2503. The CPU2503 controls the display control unit 2507, the communication controlunit 2517, and the drive device 2513 in accordance with processes in theapplication program so as to cause them to execute certain operations.Data being processed may be stored in the memory 2501, and may also bestored in the HDD 2505. The application program for implementing theabove-mentioned processes may be stored in the removable disk 2511 thatis readable by a computer, distributed, and installed from the drivedevice 2513 on the HDD 2505. The application program may be installed onthe HDD 2505 via a network, such as the Internet, and the communicationcontrol unit 2517. In the computer apparatus, the above-mentionedvarious functions may be executed by causing hardware, such as the CPU2503 and the memory 2501, and programs, such as the OS and theapplication program, to work together organically.

For example, an information processing system includes a plurality ofnodes that execute data transfer and a management apparatus that managesthe plurality of nodes. The management apparatus may include a datastorage unit that stores a priority level of data transfer and anidentifier of a node that executes the data transfer which areassociated with an identifier of the data transfer. The managementapparatus may include an identification unit that, when receiving anexecution instruction containing information of data transfer to beexecuted, identifies one or a plurality of first nodes that execute datatransfer having a lower priority level than a priority level containedin the information of the data transfer to be executed from the datastorage unit. The management apparatus may include a transmission unitthat, to each of the one or the plurality of first nodes identified bythe identification unit, transmits a stop request to stop the datatransfer executed by the first node, and also transmits a transferrequest containing the information of the data transfer to be executedand information of a portion to be executed by the first node of thedata transfer to be executed.

In the information processing system in which the plurality of nodesexecute data transfer, data transfer may be flexibly executed inaccordance with priority levels.

The management apparatus may further include a reception unit thatreceives, from each of the one or the plurality of first nodes, aresponse containing a transfer source data name, a transfer destinationdata name, information indicating a position at which the first node hasstopped transfer, and information of a remaining data size, and storesthe response in a second data storage unit. The data transfer stopped bythe first node may be executed by another node.

The identification unit may identify a second node that satisfies acertain condition among nodes other than the one or the plurality offirst nodes from the data storage unit. The transmission unit mayextract one or a plurality of responses stored in the second datastorage unit, and transmit the one or the plurality of responses to thesecond node identified by the identification unit. The stopped datatransfer may be resumed, and thus the number of data re-transferoperations may be reduced.

The identification unit may calculate the number N of nodes to beassigned to the data transfer to be executed based on information of thesize of data to be transferred by the data transfer to be executed andinformation of a time when the data transfer to be executed is completedthat are contained in the information of the data transfer to beexecuted. The identification unit may identify identifiers of an Nnumber of first nodes from among identifiers of the one or the pluralityof first nodes identified. The data transfer to be executed may becompleted by a specified time.

Each of the plurality of nodes may execute a process of checking whetheror not the node has received a stop request from the managementapparatus every time the node transfers a certain amount of data. Adelay in detection of reception of a stop request may be reduced, and adelay in starting the data transfer to be executed may be reduced.

The certain condition may include at least one of a condition on aposition of a node in a network and a condition on a processing load ofthe node. Influence on data transfer being executed may be reduced.

A control method of an information processing system is executed in aninformation processing system including a plurality of nodes thatexecute data transfer and a management apparatus that manages theplurality of nodes. In the control method of the information processingsystem, when an execution instruction containing information of datatransfer to be executed is received, one or a plurality of first nodesthat execute data transfer having a lower priority level than a prioritylevel contained in the information of the data transfer to be executedmay be identified from a data storage unit that stores a priority levelof data transfer and an identifier of a node that executes the datatransfer which are associated with an identifier of the data transfer.To each of the one or the plurality of first nodes identified, a stoprequest to stop the data transfer executed by the first node may betransmitted. A transfer request containing the information of the datatransfer to be executed and information of a portion to be executed bythe first node of the data transfer to be executed may be transmitted.

A program for causing a computer to execute the above-mentionedprocesses may be created. The program may be stored in computer-readablestorage media or storage devices, such as a flexible disk, a compactdisc read only memory (CD-ROM), a magnetic optical disk, a semiconductormemory, and a hard disk. An intermediate processing result may betemporarily stored in a storage device, such as a main memory.

All examples and conditional language recited herein are intended forpedagogical purposes to aid the reader in understanding the inventionand the concepts contributed by the inventor to furthering the art, andare to be construed as being without limitation to such specificallyrecited examples and conditions, nor does the organization of suchexamples in the specification relate to a showing of the superiority andinferiority of the invention. Although the embodiment of the presentinvention has been described in detail, it should be understood that thevarious changes, substitutions, and alterations could be made heretowithout departing from the spirit and scope of the invention.

What is claimed is:
 1. An information processing system comprising: amanagement apparatus, coupled to a plurality of nodes configured toexecute data transfer, configured to manage the plurality of nodes,wherein the management apparatus preforms operations to: acquire datatransfer information in which a priority level of data transfer and anidentifier of a node that executes the data transfer are associated withan identifier of the data transfer; identify, when receiving anexecution instruction of first data transfer, one or more first nodesthat execute second data transfer having a lower priority level than apriority level included in information of the first data transfer basedon the data transfer information; and transmit, to each of the one ormore first nodes, a stop request to stop the second data transfer, and atransfer request including the information of the first data transferand information of a portion to be executed by the first node of thefirst data transfer to be executed by the first node.
 2. The informationprocessing system according to claim 1, wherein the management apparatusreceives, from each of the one or more first nodes, a response includingtransfer source information, transfer destination information,information of a position of stopping the second data transfer, and sizeinformation of data that is not transferred.
 3. The informationprocessing system according to claim 2, wherein the management apparatusidentifies a second node that is a node other than the one or more firstnodes and satisfies a condition.
 4. The information processing systemaccording to claim 3, wherein the management apparatus transmits theresponse of each of the one or more first nodes to the second node. 5.The information processing system according to claim 1, wherein themanagement apparatus calculates a number N to be assigned to the firstdata transfer from among the one or more first nodes based on sizeinformation of data to be transferred by the first data transfer andinformation of a time when the first data transfer is completed that areincluded in the information of the first data transfer.
 6. Theinformation processing system according to claim 5, wherein themanagement apparatus identifies identifiers N nodes from the datatransfer information.
 7. The information processing system according toclaim 1, wherein each of the plurality of nodes checks a reception ofthe stop request at a time of data transfer.
 8. The informationprocessing system according to claim 3, wherein the condition includesat least one of a condition on a position of a node in a network thatincludes the plurality of nodes and the management apparatus and acondition on a processing load of the node.
 9. An information managementapparatus comprising: a processor configured to execute a program; and amemory configured to store the program, wherein, based on the program,the processor performs operations to: acquire data transfer informationin which a priority level of data transfer and an identifier of a nodethat executes the data transfer are associated with an identifier of thedata transfer; identify, when receiving an execution instruction offirst data transfer, identifies one or more first nodes that executesecond data transfer having a lower priority level than a priority levelincluded in information of the first data transfer based on the datatransfer information; and transmit, to each of the one or more firstnodes, a stop request to stop the second data transfer, and a transferrequest including the information of the first data transfer andinformation of a portion of the first data transfer to be executed bythe first node.
 10. The information management apparatus according toclaim 9, wherein the processor receives, from each of the one or morefirst nodes, a response including transfer source information, transferdestination information, information of a position of stopping thesecond data transfer, and size information of data that is nottransferred.
 11. The information management apparatus according to claim10, wherein the processor identifies a second node that is a node otherthan the one or more first nodes and satisfies a condition.
 12. Theinformation management apparatus according to claim 11, wherein theprocessor transmits the response of each of the one or more first nodesto the second node.
 13. The information management apparatus accordingto claim 9, wherein the processor calculates a number N to be assignedto the first data transfer from among the one or more first nodes basedon size information of data to be transferred by the first data transferand information of a time when the first data transfer is completed thatare included in the information of the first data transfer.
 14. Theinformation management apparatus according to claim 13, wherein theprocessor identifies identifiers N nodes from the data transferinformation.
 15. The information management apparatus according to claim11, wherein the condition includes at least one of a condition on aposition of a node in a network that includes a plurality of nodes andthe management apparatus and a condition on a processing load of thenode.
 16. A data transfer control method comprising: acquiring datatransfer information in which a priority level of data transfer and anidentifier of a node that executes the data transfer are associated withan identifier of the data transfer; identifying, with a processor, inresponse to reception of an execution instruction of first datatransfer, one or more first nodes that execute second data transferhaving a lower priority level than a priority level included ininformation of the first data transfer from among a plurality of nodesincluded in a network based on the data transfer information; andtransmitting, to each of the one or more first nodes, a stop request tostop the second data transfer, and a transfer request including theinformation of the first data transfer and information of a portion ofthe first data transfer to be executed by the first node.
 17. The datatransfer control method according to claim 16, further comprising:receiving, from each of the one or more first nodes, a responseincluding transfer source information, transfer destination information,information of a position of stopping the second data transfer, and sizeinformation of data that is not transferred.
 18. The data transfercontrol method according to claim 17, further comprising: identifying asecond node that is a node other than the one or more first nodes andsatisfies a condition.
 19. The information management apparatusaccording to claim 18, further comprising: transmitting the response ofeach of the one or more first nodes to the second node.
 20. The datatransfer control method according to claim 16, further comprising:calculating a number N to be assigned to the first data transfer fromamong the one or more first nodes based on size information of data tobe transferred by the first data transfer and information of a time whenthe first data transfer is completed that are included in theinformation of the first data transfer.